8,156 research outputs found
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Skills, government intervention and business performance: implications for the regional skills partnership (RSP)
The aim of this briefing paper is to provide an understanding of the factors that determine the level of skills in the economy, the level and type of skills demanded by employers, and how these are translated into performance improvements by individual employees. The paper deals with these questions at the national and regional level, at the level of the firm and finally of the individual employee. It then uses this knowledge to identify the range of alternative measures available to policy makers
Metallurgy of armour exhibited at the Palace Armoury, Valletta, Malta
The metallurgy of ten armour pieces from the Palace Armoury Collection in Malta was examined. Results showed that out of ten artefacts examined, six were produced in low carbon steel, one from a high carbon steel and three were made from wrought iron. One of the wrought iron armour pieces was fabricated from a phosphoric iron, an unusual material for these artefacts. All the steel artefacts exhibited a ferrite-pearlite microstructure. In their manufacture, no attempts had been made at producing martensite by full or slack quenching. All metal fragments contained slag inclusions. The elongated nature of the latter suggested that these artefacts were forged into shape.peer-reviewe
The effect of timing noise on targeted and narrow-band coherent searches for continuous gravitational waves from pulsars
Most searches for continuous gravitational-waves from pulsars use Taylor
expansions in the phase to model the spin-down of neutron stars. Studies of
pulsars demonstrate that their electromagnetic (EM) emissions suffer from
\emph{timing noise}, small deviations in the phase from Taylor expansion
models. How the mechanism producing EM emission is related to any continuous
gravitational-wave (CW) emission is unknown; if they either interact or are
locked in phase then the CW will also experience timing noise. Any disparity
between the signal and the search template used in matched filtering methods
will result in a loss of signal-to-noise ratio (SNR), referred to as
`mismatch'. In this work we assume the CW suffers a similar level of timing
noise to its EM counterpart. We inject and recover fake CW signals, which
include timing noise generated from observational data on the Crab pulsar.
Measuring the mismatch over durations of order months, the effect is
for the most part found to be small. This suggests recent so-called
`narrow-band' searches which placed upper limits on the signals from the Crab
and Vela pulsars will not be significantly affected. At a fixed observation
time, we find the mismatch depends upon the observation epoch. Considering the
averaged mismatch as a function of observation time, we find that it increases
as a power law with time, and so may become relevant in long baseline searches.Comment: 9 pages, 5 figure
Neutron Star Merger Remnants: Braking Indices, Gravitational Waves, and the Equation Of State
The binary neutron star merger GW170817/GRB170817A confirmed that at least
some neutron star mergers are the progenitors of short gamma-ray bursts. Many
short gamma-ray bursts have long-term x-ray afterglows that have been
interpreted in terms of post-merger millisecond magnetars---rapidly rotating,
highly magnetised, massive neutron stars. We review our current understanding
of millisecond magnetars born in short gamma-ray bursts, focusing particularly
three main topics. First, whether millisecond magnetars really do provide the
most plausible explain for the x-ray plateau. Second, determining and observing
the gravitational-wave emission from these remnants. Third, determining the
equation of state of nuclear matter from current and future x-ray and
gravitational-wave measurements.Comment: Conference Proceedings of the Xiamen-CUSTIPEN Workshop on the EOS of
Dense Neutron-Rich Matter in the Era of Gravitational Wave Astronomy (January
3 - 7, 2019, Xiamen, China
Comparing models of the periodic variations in spin-down and beam-width for PSR B1828-11
We build a framework using tools from Bayesian data analysis to evaluate
models explaining the periodic variations in spin-down and beam-width of PSR
B1828-11. The available data consists of the time averaged spin-down rate,
which displays a distinctive double-peaked modulation, and measurements of the
beam-width. Two concepts exist in the literature that are capable of explaining
these variations; we formulate predictive models from these and quantitatively
compare them. The first concept is phenomenological and stipulates that the
magnetosphere undergoes periodic switching between two meta-stable states as
first suggested by Lyne et al. The second concept, precession, was first
considered as a candidate for the modulation of B1828-11 by Stairs et al.. We
quantitatively compare models built from these concepts using a Bayesian
odds-ratio. Because the phenomenological switching model itself was informed by
this data in the first place, it is difficult to specify appropriate
parameter-space priors that can be trusted for an unbiased model comparison.
Therefore we first perform a parameter estimation using the spin-down data, and
then use the resulting posterior distributions as priors for model comparison
on the beam-width data. We find that a precession model with a simple circular
Gaussian beam geometry fails to appropriately describe the data, while allowing
for a more general beam geometry provides a good fit to the data. The resulting
odds between the precession model (with a general beam geometry) and the
switching model are estimated as in favour of the precession
model.Comment: 20 pages, 15 figures; removed incorrect factor of (2\pi) from
equation (15), allowed for arbitrary braking index, and revised prior ranges;
overall conclusions unchange
Validation of a Novel Approach to Solving Multibody Systems Using Hamilton\u27s Weak Principle
A novel approach for formulating and solving for the dynamic response of multibody systems has been developed using Hamiltonâs Law of Varying Action as its unifying principle. In order to assure that the associated computer program is sufficiently robust when applied across a wide range of dynamic systems, the program must be verified and validated. The purpose of the research was to perform the verification and validation of the program. Results from the program were compared with closed-form and numerical solutions of simple systems, such as a simple pendulum and a rotating pendulum. The accuracy of the program for complex systems for which there is no closed-form solution, such as a double pendulum and others, were assessed by calculating energy conservation and constraint violation. The results of this research confirm the validity of this novel approach to multibody system analysis, and pave the way for its application to increasingly complex configurations
Professional Growth: How do Cooperating Teachers Grow Through the Experience of Having a Student Teacher?
Cooperating teachers and student teachers share a unique internship that allows the development of skills for both individuals. The literature states that cooperating teachers can grow from student teachers; however, there are a few sources that state the areas in which this growth occurs. The purpose of this study was to determine if growth or impact happened in the areas of instructional practices, coaching skills, and self-efficacy during the student teaching process. This mixed methods study included a survey, focus group interview, and single interviews to determine whether any change was made. The survey created descriptive statistics, a Pearson correlation test, and interviews to balance the quantitative and qualitative data. The findings revealed that student teachers had an impact on instructional practices within the survey, focus group, and interviews. Coaching skills and self-efficacy revealed the impact was subtle as it showed in the positive correlation. The significance of these was that teachers reflect more because of the student teacher process and thus become better teachers; this leads to higher student achievement. Cooperating teachers pass on their knowledge to student teachers and colleagues by working together in collaboration and teaming to do what is best for the students
Diving Demand for Large Ship Artificial Reefs
Using data drawn from a web-based travel cost survey, we jointly model revealed and stated preference trip count data in an attempt to estimate the recreational use value from diving the intentionally sunk USS Oriskany. Respondents were asked to report their: (i) actual trips from the previous year, (ii) anticipated trips in the next year, and (iii) anticipated trips next year assuming a second diveable vessel (a Spruance class destroyer) is sunk in the same vicinity. Results from several different model specifications indicate average per-person, per-trip use values range from 750. The ââŹĹbundlingâ⏠of a second vessel in the area of the Oriskany to create a multiple-ship artificial reef area adds between 1,160 per diver per year in value.Artificial reefs, diving, recreation demand, combined revealed and stated preferences, non-market valuation, Institutional and Behavioral Economics, Marketing, Productivity Analysis, Public Economics, Research Methods/ Statistical Methods, Q26, Q50,
The vector innovation structural time series framework: a simple approach to multivariate forecasting
The vector innovation structural time series framework is proposed as a way of modelling a set of related time series. Like all multi-series approaches, the aim is to exploit potential inter-series dependencies to improve the fit and forecasts. A key feature of the framework is that the series are decomposed into common components such as trend and seasonal effects. Equations that describe the evolution of these components through time are used as the sole way of representing the inter-temporal dependencies. The approach is illustrated on a bivariate data set comprising Australian exchange rates of the UK pound and US dollar. Its forecasting capacity is compared to other common single- and multi-series approaches in an experiment using time series from a large macroeconomic database.Vector innovation structural time series, state space model, multivariate time series, exponential smoothing, forecast comparison, vector autoregression.
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